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Biomedical subjects

K Toda

Publications and source records attributed to K Toda.

At least 325 records · Page 18Linked to original sources

Diazepam-induced suppression of jaw opening reflex in rats.

Effec of an i.p. injection of diazepam on the jaw opening reflex evoked by electrical stimuli applied to the tooth pulp innervated by mainly high threshold afferents and the lower lip innervated by low threshold afferents was investigated using Wistar albino rats. Small doses of diazepam, less than 2.5 mg/kg, suppressed to the same degree the jaw opening reflexes evoked by stimulation of tooth pulp or lower lip. However, when larger doses thab 5.0 mg/kg were administered, the suppression of tooth pulp-evoked jaw opening reflex was greater than that of lower lip-evoked one. In this case, the period of suppression of tooth pulp-evoked jaw opening reflex was longer than that of lower lip-evoked one. It is concluded that (1) the pain relieving effect of diazepam appears only when larger doses tha 5.0 mg/kg are administered and that (2) the pain-relieving effect lasts longer than muscle-relaxative effect of diazepam.

Analgesics↗

Effective conditions of electroacupuncture stimulation for suppressing tooth pulp-evoked jaw-opening reflex in the rat.

The effects of electroacupuncture (EA) on the rat jaw-opening reflex elicited by tooth pulp stimulation were studied to decide the effective stimulus conditions for electroacupuncture stimulation (EAS). The present study revealed that one of the most important factors for producing a strong EA effect was the stimulus pulse-frequency and that the stimulus pulse-duration was not an essential factor for this effect. In the rat, the following stimulus conditions were very useful for the quantitative study of the EA effect. (1) Stimulation time is 15 min. (2) Stimulus pulse-frequency is 30 to 150 Hz. (3) Stimulus pulse-duration is 0.1 to 5 ms. When the EAS was applied to the Ho-Ku point under these conditions, the degree of the suppression of the jaw-opening reflex was about 50% of the control.

Action Potentials↗

Mathematical model of cell growth and phosphatase biosynthesis in Saccharomyces carlsbergensis under phosphate limitation.

The rate kinetics of growth and acid phosphate formation in the batch culture of Saccharomyces carlsbergensis LAM 1068 was studied under varying degrees of phosphate limitation. The mathematical model that was developed is concerned with the time lag for exponential growth, the biphasic growth on a substrate (glucose) and its product (ethanol), sustained growth on conservative phosphate, and the derepression of acid phosphatase. The numerical calculations using appropriate parametric constants successfully described the variation in the cell mass, glucose, ethanol, and inorganic phosphate concentrations, and the enzyme activity of acid phosphatase during aerobic growth of S. carlsbergensis under five different conditions of phosphate starvation. A simulation study revealed that the optimum initial phosphate concentration in the medium giving a high productivity of acid phosphatase was 2.0 mg phosphorus/g glucose liter.

Acid Phosphatase↗

Malignant teratoma of the thyroid gland in an adolescent female.

Malignant teratoma of the thyroid gland was found in a 19-year-old female. She was given a combined surgical and irradiation treatment. The tumor was 5.0X4.0X3.6 cm and located in the lower right lobe of the thyroid gland. Light and electron microscopical examination revealed mature or immature derivatives of the three primordial germ layers. The dominant portion of the tumor was composed of numerous masses of cancerous epithelial cells, which were distributed randomly in the mesenchymal tissue. Tumor cells invaded and replaced the surrounding thyroid tissue with occasional tumor thrombi in the lumens of blood vessels. No metastatic tumor was found in the lymph nodes. The patient was given a course of external irradiation, a total dose of 4000 rads, to the right thyroid area. Eight months after surgery, she is well and without any evidence of recurrence or metastasis.

Adult↗

Effects of diazepam (cercine) on the somatosensory evoked responses following tooth pulp stimulation in rat.

Effect of diazepam on the somatosensory evoked responses (SER) following tooth pulp stimulation was investigated in Wistar albino rats. The SERs were recorded from the contralateral surface of the skull with a silver ball electrode and 200 responses were averaged with a medical computer. Generally, SERs were found to be composed of a sequence of four components named P1 (first positive wave), N1 (first negative wave), P2 (second positive wave), and N2 (second negative wave) in a 100 msec analysis time. Diazepam enhanced only the amplitude of the P1 component to about 500% of the control, while it suppressed other N1, P2, and N2 components to about 30, 40, and 20% of the control, respectively. The maximum suppressed effect appeared about 30 min after the diazepam injection and the effect was maintained for about 150 min. One possible explanation for the present result is that the activities of the synapses mostly in cortical layter IV evoked by tooth pulp stimulation may be enhanced but the activities of the cortical cells may be suppressed by diazepam injection.

Animals↗